A variety of different sole constructions are used by the footwear industry. For the most part, each sole construction has characteristics that make it particularly well-suited for specific applications. For example, some constructions are selected for their durability, others for their comfort, while still others are selected for their aesthetic appeal.
Some shoes typically have enhanced cushioning, which may result in a softer feel to a user's foot. Moreover, cushioning may be used or enhanced in any area of the shoe. Generally, the more cushioning, the softer the shoe feels to the user, resulting in improved comfort. However, increasing cushioning may lead to an increased likelihood of retaining moisture and/or bacteria in the cushioning material. Therefore, adding cushioning may also disadvantageously introduce odors or fungi.
Some footwear often comprises a midsole, where an upper is attached to a top surface of the midsole and a wear surface is attached to a bottom surface of the midsole. Because the wear surface is usually in contact with the ground, the midsole need not be, and is often not, made of a material as tough or rigid as the wear surface. However, because the midsole should resist breaking down while providing structural integrity in connecting the upper and wear surface, as well as support to the shoe, the midsole is generally tougher than cushioning material. In other types of footwear, the midsole and wear surface are combined and such combination is usually called an outsole.
Whether a shoe uses a midsole or outsole, consumers often use comfort as at least one basis for purchasing a particular shoe over a competitor's shoe. Therefore, manufacturers have longed to improve comfort of their shoes, which is often achieved by placing resilient or cushioning material between a user's foot and a top surface of the midsole or outsole. However, due to repeated foot strikes, particularly in the heel and balls of the foot areas, the cushioning material often breaks down or becomes flattened. In some cases, the breakdown of the cushioning is so severe that the user may discard the shoe even though other parts of the shoe are usable.
In other types of footwear, an insole may be provided in direct contact with the upper around a periphery of the insole so as to form a cavity into which a foot may be placed. The midsole may be in direct contact with the bottom of the insole to secure the wear surface to the insole and upper. For stitched shoes, the midsole may be sewn to the insole. In cemented shoes, the midsole may be adhered to the insole.
Similar to the midsole, the insole is often of a rigid material so that it may provide adequate structural integrity and be capable of being stitched. However, since the insole is not in contact with the ground, it need not be as tough as the wear material.
Therefore, since both the insole and midsole are typically used to provide structural integrity, their ability to provide cushioning and/or flexibility may be limited.
U.S. Pat. No. 2,598,297 (“Pierson”) appears to relate to a cushioned insole. However, Pierson may not address the midsole's cushioning and/or flexibility.
U.S. Pat. No. 4,930,232 (“Engle”) appears to relate to a multilayered sole for enhancing comfort. However, Engle seems to rely upon the combination of layers to provide overall relief but may not address the need to improve the cushioning and/or flexibility of each of the individual layers, such as the insole or midsole. Engle may also not address the build up of fungi or odors in its layers of cushioning materials.
U.S. Pat. No. 4,979,318 (“Cohen”), U.S. Pat. No. 5,014,706 (“Philipp”) all seem to relate to orthodics and, in some cases, flexible orthodics. However, these patents do not seem to enhance comfort and/or flexibility of the midsole and the insole.
U.S. Pat. No. 4,908,961 (“Purslow”), U.S. Pat. No. 2,691,227 (“Sachs”), U.S. Pat. No. 492,994 (“Sawyer”), U.S. Pat. No. 1,947,031 (“Bain”), U.S. Pat. No. 4,633,877 (“Pendergast”), and U.S. Pat. No. 4,627,177 (“Meyers”) all seem to relate to insoles but may not address the midsole's flexibility and/or cushioning.
What is desired, therefore, is an insole with improved flexibility and cushioning without sacrificing structural integrity. Another desire is a midsole with improved flexibility and cushioning without sacrificing structural integrity. Yet another desire is an insole and midsole that provides enhanced cushioning while reducing odors and bacteria.